ABSTRACT The Retroviral Nucleocapsid and Assembly Symposium (IRNCS) has historically focused on the biological role of the NC protein in HIV-1 and other retroviruses. The last installment of the meeting was held in Montpellier, France in September of 2016. At the Montpellier meeting, we emphasized the role of NC/Gag in assembly, and we plan to continue this emphasis for the Boston meeting, as there has been significant progress in this exciting area. Approximately 100-120 researchers worldwide have typically participated in this symposium in an effort to generate a complete picture of the role of NC in retroviral pathogenesis. NC plays critical roles in (1) remodeling host and viral nucleic acids as a chaperone protein, (2) assembly and targeting the retroviral genomic RNA to new virus particles, and (3) protecting viral DNA and facilitating integration into host DNA. Some of these functions are performed by NC as part of the precursor Gag protein, and others are carried out by mature NCp7. More recent work shows that NC plays roles immediately following infection and in 2012, a role in retroviral restriction was discovered. NC therefore represents a suitable target for therapy. The symposium will provide a venue for researchers (principal investigators, postdoctoral fellows, students, research staff and representatives from biotechnology) to make progress in efforts to combat HIV-1/AIDS, as well as other retroviral diseases, by focusing on this central player in the viral lifecycle. The IRNCAS has a long-standing record of research excellence, of promoting research collaborations, supporting young scientists, and including women and other individuals who have been traditionally underrepresented in science. The major topics discussed during this Symposium will be focused on the HIV-1 nucleocapsid; however, other nucleocapsids of viruses causing human pathologies (HTLV, Hepatitis and Influenza) will be also considered. Special attention will be given to the implication of the NC domain of the Gag protein in the viral RNA sequestration and assembly of HIV-1, the interactions of NC with viral and cellular partners, chaperone properties, the impact of biophysical methods, notably high-resolution microscopy and NMR on the understanding of these processes, and the development of therapeutic strategies. The Retroviral NC Symposium has a long-standing record of research excellence, of promoting research collaborations, supporting young scientists, and including women and other individuals who have been traditionally underrepresented in science.